I’ve been working on a little project on flutter since I just started learning it a week ago and I’m just wondering how I could retrieve and use a specific snippet of data from Firebase’s Firestore database.

Hello and welcome,
I’ve taken a fast glance at your code to try to answer your specific question about the app bar title.

In DatabaseMethods class you have a getSpecificUserData(String uid) method, which is returning the name of a user given his uid.
But in Profile (profile.dart), you are invoking a databaseMethods.retrieveData(user.uid) method instead, which I couldn’t find implemented in the DatabaseMethods class.

Also I’m not sure if you want to display the name or the handle. Let’s say it is the name (for the above returned value).

I’m just guessing here, maybe you could have the app bar title updated with the user’s name with something like: